svn commit: r354723 - in head/sys: powerpc/include sys

[Justin Hibbits]

Author: jhibbits
Date: Fri Nov 15 04:33:07 2019
New Revision: 354723
URL: https://svnweb.freebsd.org/changeset/base/354723

Log:
  atomic: Add atomic_cmpset_masked to powerpc and use it
  
  Summary:
  This is a more optimal way of doing atomic_compset_masked() than the
  fallback in sys/_atomic_subword.h.  There's also an override for
  _atomic_fcmpset_masked_word(), which may or may not be necessary, and is
  unused for powerpc.
  
  Reviewed by:	kevans, kib
  Differential Revision:	https://reviews.freebsd.org/D22359

Modified:
  head/sys/powerpc/include/atomic.h
  head/sys/sys/_atomic_subword.h

Modified: head/sys/powerpc/include/atomic.h
==============================================================================
--- head/sys/powerpc/include/atomic.h	Fri Nov 15 03:40:02 2019	(r354722)
+++ head/sys/powerpc/include/atomic.h	Fri Nov 15 04:33:07 2019	(r354723)
@@ -608,6 +608,38 @@ atomic_cmpset_short(volatile u_short *p, u_short cmpva
 
 	return (ret);
 }
+#else
+static __inline int
+atomic_cmpset_masked(uint32_t *p, uint32_t cmpval, uint32_t newval,
+    uint32_t mask)
+{
+	int		ret;
+	uint32_t	tmp;
+
+	__asm __volatile (
+		"1:\tlwarx %2, 0, %2\n\t"	/* load old value */
+		"and %0, %2, %7\n\t"
+		"cmplw %4, %0\n\t"		/* compare */
+		"bne- 2f\n\t"			/* exit if not equal */
+		"andc %2, %2, %7\n\t"
+		"or %2, %2, %5\n\t"
+		"stwcx. %2, 0, %3\n\t"      	/* attempt to store */
+		"bne- 1b\n\t"			/* spin if failed */
+		"li %0, 1\n\t"			/* success - retval = 1 */
+		"b 3f\n\t"			/* we've succeeded */
+		"2:\n\t"
+		"stwcx. %2, 0, %3\n\t"       	/* clear reservation (74xx) */
+		"li %0, 0\n\t"			/* failure - retval = 0 */
+		"3:\n\t"
+		: "=&r" (ret), "=m" (*p), "+&r" (tmp)
+		: "r" (p), "r" (cmpval), "r" (newval), "m" (*p),
+		  "r" (mask)
+		: "cr0", "memory");
+
+	return (ret);
+}
+
+#define	_atomic_cmpset_masked_word(a,o,v,m) atomic_cmpset_masked(a, o, v, m)
 #endif
 
 static __inline int

Modified: head/sys/sys/_atomic_subword.h
==============================================================================
--- head/sys/sys/_atomic_subword.h	Fri Nov 15 03:40:02 2019	(r354722)
+++ head/sys/sys/_atomic_subword.h	Fri Nov 15 04:33:07 2019	(r354723)
@@ -63,6 +63,7 @@
     ((((__uintptr_t)(p) % 4)) * NBBY)
 #endif
 
+#ifndef	_atomic_cmpset_masked_word
 /*
  * Pass these bad boys a couple words and a mask of the bits you care about,
  * they'll loop until we either succeed or fail because of those bits rather
@@ -92,7 +93,9 @@ _atomic_cmpset_masked_word(uint32_t *addr, uint32_t ol
 
 	return (ret);
 }
+#endif
 
+#ifndef	_atomic_fcmpset_masked_word
 static __inline int
 _atomic_fcmpset_masked_word(uint32_t *addr, uint32_t *old, uint32_t val,
     uint32_t mask)
@@ -108,6 +111,7 @@ _atomic_fcmpset_masked_word(uint32_t *addr, uint32_t *
 	*old = (*addr & ~mask) | *old;
 	return (atomic_fcmpset_32(addr, old, (*old & ~mask) | val));
 }
+#endif
 
 static __inline int
 atomic_cmpset_8(__volatile uint8_t *addr, uint8_t old, uint8_t val)